#32673 – /dev/net/tun is created as a regular file if missing

Bug 32673 - /dev/net/tun is created as a regular file if missing

Summary: /dev/net/tun is created as a regular file if missing

Status:	NEW

Alias:	None

Product:	Sisyphus
Classification:	Development
Component:	vpnc-script (show other bugs)
Version:	unstable
Hardware:	all Linux

Importance:	P3 minor
Assignee:	Alexey Shabalin
QA Contact:	qa-sisyphus

URL:
Keywords:

Depends on:
Blocks:

Reported:	2016-10-27 14:43 MSK by Ivan Zakharyaschev
Modified:	2026-09-09 12:17 MSK (History)
CC List:	1 user (show)

See Also:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.

Description

Ivan Zakharyaschev 2016-10-27 14:43:27 MSK

vpnc-script-0.5.3-alt6

In a system without systemd (and without any preceding "modprobe tun"), openconnect (which must be using vpnc-script):

* would fail with unclear errors like this:

	ioctl(5, TUNSETIFF, 0x7fffbc71f7d0) = -1 ENOTTY (Inappropriate ioctl for device)

* and would have created /dev/net/tun as a regular file like this:

	open("/dev/net/tun", O_RDWR|O_CREAT, 0666) = 3

(which would prevent the creation of a correct device afterwards).

A similar case (probably, the same bug) has been reported as a Debian bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780709

Work-around:

rm /dev/net/tun # if it's a wrong regular file
modprobe -r tun
modprobe tun

Comment 1

Anton Farygin 2026-09-09 12:17:35 MSK

Проверка актуальности: актуально. В vpnc-script 0.5.3-alt7 строка 575: `if (exec 6<> /dev/net/tun) > /dev/null 2>&1` — открытие через `<>` идёт с O_CREAT, поэтому при отсутствии узла устройства создаётся обычный файл /dev/net/tun, и последующая ветка с mknod (строки 585–587) уже не срабатывает. Достаточно заменить проверку на `[ -c /dev/net/tun ]` или открывать через `<`.